This invention relates to nonwoven webs treated with a stable aqueous formulation containing petrolatum. The invention includes a foaming process for applying the petrolatum formulation to the nonwoven web.
A number of products made of nonwoven fabrics, such as personal care absorbent products, interact with a user""s skin. Various skin disorders are often associated with use of personal care absorbent products. Diaper rash is a prime example of a skin disorder often caused, in part, by friction between a nonwoven fabric and a user""s skin. A number of preventive measures have been developed and used over the years, such as topical application of creams and lotions, in order to prevent or cure diaper rash.
Skin barrier dysfunction is often associated with the loss of material and structure in the lipid-containing domains of the skin. One area of skin care product development is lipid replenishment by the external application of lotions supplemented with specific components known to be present in-vivo. Use of barrier creams, such as those containing petrolatum or mineral oil, is also common. These barrier creams typically act by occluding the skin with a hydrophobic coating. Petrolatum-based lotions are differentiated from high-value lotions containing botanical extracts in that the latter are intended to deliver an active ingredient, ostensibly to the skin.
U.S. Pat. Nos. 5,635,191 to Roe et al., 5,609,587 to Roe, and 5,643,588 to Roe et al. disclose non-aqueous waxes, striped applications, and substrates that are non-permeable by water.
Petrolatum-based lotions effectively prevent or reduce the occurrence of a number of common skin disorders. However, such lotions must be applied directly to the skin between each use of a nonwoven personal care absorbent garment, resulting in a time-consuming, often messy ritual. There is a need or desire for a topical treatment for a nonwoven substrate that can prevent or reduce the occurrence of a number of common skin disorders associated with nonwoven personal care absorbent garments. There is also a need or desire for an efficient method of applying a topical treatment to a nonwoven substrate.
In response to the discussed difficulties and problems encountered in the prior art, a new topical treatment for nonwoven substrates has been discovered. The topical treatment is a petrolatum oil-in-water emulsion. While maintaining acceptable fluid handling performance and skin hydration for the nonwoven substrate, this surface treatment is capable of delivering petrolatum to a user""s skin upon substrate/skin contact. In addition, substrate softness is improved in comparison to similar, non-treated nonwoven substrates.
The topical treatment can be delivered to the nonwoven substrate by a number of various methods, including foaming, spraying, saturation dipping and high solids centrifugal application. The foaming method is accomplished by supplying petrolatum, water, air, and, optionally, an alkylated glycoside or other foaming aid to a mixing chamber, generating foam in the mixing chamber, and applying the foam to the nonwoven substrate via nozzle applicators. This method is compatible with existing commercial nonwoven production equipment.
The petrolatum emulsion is stable and possesses desirable Theological properties for in-process and in-use applications. Water insoluble additives, such as oils of botanical extracts, can be easily incorporated into the dispersion without negative effects. These oils can be delivered to the user""s skin upon substrate/skin contact, along with the petrolatum. The treated nonwoven substrate can be used as a liner in various personal care garments, including diapers, wet wipes, training pants, feminine hygiene articles, and incontinence articles.
With the foregoing in mind, it is a feature and advantage of the invention to provide a surface modified nonwoven fabric capable of delivering petrolatum to skin upon material/skin contact.
It is also a feature and advantage of the invention to provide an efficient process for applying a petrolatum emulsion to a nonwoven substrate using existing commercial nonwoven production equipment.